Rare G3P[3] rotavirus strain detected in Brazil: Possible human-canine interspecies transmission

Background: An unusual strain of human rotavirus G3P[3] (R2638 strain) was detected from a 1-year-old child patient during the epidemiological survey of rotavirus in the state of Sao Paulo, Brazil in 2011. Objective: The aim of this study was to carry out sequence analyses of the two outer capsid proteins (VP4 and VP7) of the R2638 strain detected in order to obtain further information of the genetic relationships between human and animal rotaviruses. Study design: Rotavirus G3P[3] was detected using a commercial immunoenzymatic assay, SDS-PAGE, and genotyped by RT-PCR. The analysis of the genetic relationship between human and animal rotaviruses was carried out by sequencing the VP7 and VP4 genes. Results: The VP7 gene of the R2638 strain displayed the highest nucleotide identity to the canine strains A79-10 (96.6%) and CU-1 (96.2%) isolated in USA. The VP4 sequence showed the highest nucleotide identity to P[3] canine rotavirus strain RV52/96 isolated in Italy at 94.1%. Furthermore, the VP4 genes of P[3] strains could be discriminated into two phylogentically distinct clusters. Conclusion: The present study reinforces the hypothesis that animal's rotaviruses might be able to cross the species barriers, and the lack of systematic surveillance of rotavirus infection in small animals hinders the ability to establish firm epidemiologic connections. Moreover, in 2006 rotavirus vaccine was included in the Brazilian Immunization Program, and selective vaccine pressure could increase the circulation of uncommon strains. This is the first report of G3P[3] in over 20-year period of monitoring in Brazil. (C) 2012 Elsevier B. V. All rights reserved.